They appealed Thursday to the Army Court of Criminal Appeals after the trial judge rejected their request to dismiss the charges.

McCain said last year that if Bergdahl isn't punished, his Senate Armed Services Committee would hold a hearing. Legal experts have said that McCain's comment could be seen as a threat to the careers of military officers who decide otherwise.

Weeks later, a general sent the case to a general court martial.

Bergdahl, who left his post in Afghanistan in 2009 and was held five years by the Taliban and its allies, could get a life sentence if convicted of desertion and misbehavior before the enemy.